If DEFMTD is set to STD or COM, WIDTH1 is the width of a single
echelle order. To find this value load the ORDREF on the display using
LOAD/IMAGE and use for example the commands GET/CURSOR or
EXTRACT/TRACE and PLOT/IMAGE TRACE. A superior method which will
be needed later in the reduction any way is to extract a column and to produce
a plot on the hardcopy device. Let x be a column somewhere in the middle
of the frame. The following sequence of commands
will do the job:

SET/PLOT BIN=ON
PLOT/COL ima @x
SEND/PLOT ps2usr0

The default method for DEFINE/ECHELLE is STD. However,
it happens that the order definition procedure mixes order and inter-order:
this is likely to occur in the blue where the order spacing becomes less
than the width of each order. Set the parameter DEFMTD=COM